The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9
The cargo receptor SURF4 promotes the efficient cellular secretion of PCSK9
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DOI：
10.7554/elife.38839
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发表时间：
2018-09-25
期刊：
影响因子：
7.7
通讯作者：
Ginsburg, David
中科院分区：
文献类型：
--
作者：
Emmer, Brian T.;Hesketh, Geoffrey G.;Ginsburg, David
PCSK9是一种分泌性蛋白，可调节血浆胆固醇水平和心血管疾病风险。先前的研究表明存在一种ER货物受体，将PCSK 9招募到分泌途径中，但其身份仍然难以捉摸。在这里，我们应用了一种新的方法，将邻近依赖性生物素化和蛋白质组学与基因组规模的CRISPR筛选相结合，以鉴定SURF 4，酵母货物受体Erv29p的同源物，作为HEK293T细胞中PCSK 9分泌的主要介导物。SURF4对PCSK 9分泌的功能贡献用多种独立的SURF4靶向sgRNA、克隆SURF4缺陷细胞系和SURF4 cDNA的功能拯救来证实。发现SURF 4定位于早期分泌途径，在那里它与PCSK 9物理相互作用。SURF4的缺失导致ER积累和PCSK 9的细胞外分泌减少。这些发现支持SURF 4作为ER货物受体介导PCSK 9的有效细胞分泌的模型。
PCSK9 is a secreted protein that regulates plasma cholesterol levels and cardiovascular disease risk. Prior studies suggested the presence of an ER cargo receptor that recruits PCSK9 into the secretory pathway, but its identity has remained elusive. Here, we apply a novel approach that combines proximity-dependent biotinylation and proteomics together with genome-scale CRISPR screening to identify SURF4, a homologue of the yeast cargo receptor Erv29p, as a primary mediator of PCSK9 secretion in HEK293T cells. The functional contribution of SURF4 to PCSK9 secretion was confirmed with multiple independent SURF4-targeting sgRNAs, clonal SURF4-deficient cell lines, and functional rescue with SURF4 cDNA. SURF4 was found to localize to the early secretory pathway where it physically interacts with PCSK9. Deletion of SURF4 resulted in ER accumulation and decreased extracellular secretion of PCSK9. These findings support a model in which SURF4 functions as an ER cargo receptor mediating the efficient cellular secretion of PCSK9.